Couple of troubled Powerbooks, won't power on...

[commodorejohn]

As it says, I've got a couple 68k Powerbooks (a 170 and a 180) which don't want to power on. The 180 I know worked when I got it, but evidently it reached its shelf life and now it doesn't; the 170 I'm not sure of, as I just got it from the recycle center, but it's otherwise in good shape. The AC adapter is known-good, so I don't think it's a problem with that; what else should I check in trying to restore these to life?

 

[Macdrone]

Do a search on resetting the PMU as it gets corrupted because the battery on the inverter board will not stay charged. Also leave it plugged in with battery out to charge it up a bit, then reset the PMU. So far I'm about 75% success that way. Only the 150 I have won't boot and I'm told that the in inverter board is suspect because its unique.

 

[RickNel]

Exactly this worked for me just yesterday on a Powerbook G4 15". If the PRAM battery is flat, the PMU will not allow booting or charging of the main battery. With the main battery out, leave on charger for about an hour. The power adapter input should go to green. Check the thing will boot. Then replace the main battery and it will charge up over a few hours.

You will be better off replacing the PRAM battery if possible. I started another thread on DIY PRAM battery, no responses so far.

Rick

 

[techknight]

Not a 170 or 180. I have run these with the batteries removed.

You need to smell around the DC jack area after its been plugged in for a short bit. Also main battery removed. The diodes in the DC-DC converter section has a tendency to spontaneously short, and sometimes leave evidence of burning. I got a 180C a couple years ago that wouldnt power on and had "that smell" near the DC jack area.

Found it, fixed it, works fine. I would look at them for you, but working 2 jobs now is rough and havent had time for anything anymore, not even hobbies.

 

[commodorejohn]

Well, I followed the PMU-reset procedure for both, and no luck. No smell of burning or anything, just nothing...

 

[Macdrone]

Well next bet is removing the inverter board and checking for activity when pressing the power button. If nothing you may have the same issue which I have found with my 150.

 

[commodorejohn]

Hmm, well, turns out the known-good power adapter isn't so known-good after all. Cheap Radio Shack POS...I tried it with a different adapter and the 180 is now working. No luck with the 170, though...

 

[Macdrone]

Check to make sure the voltage is correct with a multimeter. I've taken all my radio shack power supies back and got the twenty dollar Wally World ones as they are more dead on voltage wise.

 

[techknight]

Did you buy a transformer supply? or switching supply. The unregulated transformer supplies are rated for what the voltage is supposed to be at its current rating. Say, 7.5V at 1000ma. Meaning its gaurenteed to have 7.5V at 1000ma. Any lower current, voltage goes up. Sometimes i have seen it as high as 13 to 15v unloaded.